This invention relates to an Apparatus for reading the image information of the colored original in an image processing installation such as a copying machine, a printer, a facsimile machine and so on.
Apparatus is known for reading the image information of a colored original with an original supporting member, an optical system having a lamp for exposing the original placed on the original supporting member and a lens for forming an image of the original by the reflected ray from the original and a reading device for reading out information of the image separated in at least two colours and for converting the optical information into electrical output.
In such apparatus the exposing light for the original is separated in at least two colors, for example three colors such as red, green and blue and the information of the separated colors is converted to electrical signals at the reading device such as CCD etc.
The white background of the copy can be used as a measure of the quality of color reproduction. The information of the light separated in three colors is converted in electrical information in each separated colour by the reading devices such as CCD. And the outputs of each CCD in accordance with a white standard are controlled in equivalent value for improving the reappearance of the colour. In such manner a white balance controlling is carried out. A spectro-distribution characteristic at the time when the white balance is controlled can not be always maintained, so that the white balance can be changed dependent on a change of the spectro-distribution characteristic of a light source.